Police continued searching a house in Bedfordshire today as part of an investigation into the UK connections of the suicide bomber who struck in Stockholm on Saturday night.

Taimour Abdulwahab al-Abdaly, an Iraqi-born Swede who set off a car bomb in the Swedish capital before killing himself with a second bomb strapped to his body, received a BSc in sports therapy from the University of Luton, now the University of Bedfordshire, in 2004, and had spent some time in Luton in recent years.

Whitehall officials confirmed the bomber's identity, and the university said today he had spent three years there. Swedish police have yet to confirm Abdaly as the bomber but said they were 98% certain he was the culprit.

The Swedish newspaper Expressen reported that the country's security service believe the bomb went off accidentally and Abdaly had planned to set off three devices, including one at the main railway station and one at a large department store. It said he had planned to blow up his car but also had 12 pipe bombs strapped to his body, and a bomb in a rucksack.

"It is clear that he was trying to create as much chaos and hurt as many people as possible," Expressen quoted a police source as saying.

The al-Hanin site today published a photomontage including a photograph of Abdaly, suggesting he was a member of the group and carried out the Stockholm explosion. It does not directly claim responsibilty for the attack but expresses clear approval of it.

Abdaly was described as muhjahid, or fighter, and referred to on another Arabic-language Islamist internet forum as "our brother", though this phrase does not necessarily indicate any organisational affiliation.

Metropolitan police officers started examining a terrace house in Luton last night after a warrant was issued under the Terrorism Act 2000. The property remained cordoned off today.

It was reported last night that his family still lived in Luton and that neighbours last saw Abdaly two and a half weeks ago.

Abdaly's family were quoted by the Swedish press as saying they had lost contact with him. "He did not say where he was going," Abdaly's father told Expressen. "The whole family is in shock and wants to find out what happened."

Tahir Hussain, 33, a taxi driver who lives nearby, said he used to exchange greetings with Abdaly. "He had only been here about a year. I used to chat to him a bit: say good morning, good afternoon," said Hussain. "He seemed like a very nice person. I never thought he'd be like this."

He said he would see Abdaly with his three children in the garden. "His wife used to cover her face, and he wore a djellaba," Hussain said. "You could tell he was religious."

Scotland Yard said: "At 10.55pm last night Metropolitan police officers executed a search warrant under the Terrorism Act 2000 at an address in Bedfordshire. No arrests have been made and no hazardous materials found."

A police car with two officers inside was parked outside a semi-detached, bay-fronted house in Argyll Avenue in Luton today, where camera crews and reporters had gathered. There was no sign of activity inside the property.

A Home Office spokesman said officials remained in close contact with the Swedish authorities.

The Swedish newspaper Dagens Nyheter said Abdaly had travelled to Britain and Jordan in the run-up to Saturday's attack, in which he was the only victim.

On a Muslim matrimonial site, Muslima.com, where he was seeking a second wife, Abdaly, 29, listed Luton as his home, and said he had met his first wife in Bedfordshire.

However, his car was registered in Sweden, and the motives declared in emails sent to a Swedish news agency and the security police addressed local issues.

The emails refer to a Swedish cartoonist, Lars Vilks, whose 2007 drawing of the prophet Muhammad as a dog infuriated Muslims around the world, and to Sweden's 500 soldiers in Afghanistan. "Now your children, daughters and sisters shall die like our brothers and sisters and children are dying," one email warned.

The car caught fire but did not explode and caused minimal damage in a busy Stockholm shopping street. Only one of several bombs Abdaly had strapped to his body blew up, killing him but nobody else.

Sweden's prime minister, Fredrik Reinfeldt, cautioned that no connection between the emails and the bombs had been proved. "We know that a man is dead. We know that a car exploded. We know that some threat has been given to the secret police and media," he said. "But we are not sure they are connected. And I think it's very important not to give final answers based on speculation."

Downing Street said David Cameron had spoken to Reinfeldt so that the two leaders could update one another on the continuing investigation.

British intelligence sources suggested Abdaly was one of an increasing number of individuals influenced by al-Qaida ideology who have spent time in the UK. However, they said there was no indication the bomber was directed by al-Qaida – he had probably planned his own attack.

The fact that the Stockholm attack failed suggests al-Qaida is not in a position to train its supporters properly, British sources said.

Terrorism experts suggested al-Qaida and its allies were increasingly favouring one-man attacks on targets of opportunity, rather than long-planned, sophisticated and spectacular assaults such as 9/11.